This invention broadly relates to deep rolling fillets for engine crankshafts or other annular areas of metallic work pieces subject to high stress loads. More particularly, this invention relates to a new tool mechanism for deep rolling machines, wherein the tool mechanism includes a new and unique cage and retainer design for holding the work rollers.
The state-of-the-art is indicated by the following cited references: Gottschalk, U.S. Pat. No. 5,495,738; Gottschalk, et al. U.S. Pat. No. 5,445,003; Bone, U.S. Pat. No. 5,493,761; Winkens, U.S. Pat. No. 5,138,859; Berstein, U.S. Pat. No. 4,561,276; and Ostertag, U.S. Pat. No. 4,947,668. The disclosures of Lonero, et al. U.S. Pat. No. 5,699,692 and Lonero, et al. U.S. Pat. No. 5,806,184 are hereby incorporated herein by reference.
Various machines and methods have been employed to strengthen and finish metal work pieces such as crankshafts and camshafts for internal combustion engines. In many modern automobiles, engines have been downsized for installation into small vehicles. Accordingly, with downsizing of automotive vehicles and their components for reducing weight and improving fuel efficiency, smaller engines and crankshafts are often used. To improve the fatigue strength and durability of these crankshafts, deep rolling of fillets and other circular joint areas is increasingly important. The fatigue strength and durability of crank pins and main bearing journals can be significantly increased by deep rolling compressive stresses into the middle of the annular fillets between the pin journals and adjacent counter weights or balancing webs.
In previously designed tool mechanisms for deep rolling machines the cage members which hold the working rollers during the deep rolling operation are subjected to significant wear and tear. These cage members are usually made of bronze, and during the rolling operation a certain clearance is introduced to the cage members to permit proper rotation of the rollers themselves. Since the rolling operation occurs basically in one rotational direction only, the cage members also tend to wear down. As this wearing action occurs on the cage members, a gap (or excessive clearance) begins to occur or build up. This excessive clearance or gap eventually leads to improper functioning of the deep rolling tool. Those working in the art have long sought a solution to this problem.
Accordingly, one object of the present invention is to provide a novel design for a tool mechanism used in deep rolling operations wherein the cage and retainer structure for the tool mechanism is of a new and unique design.
Another object of the present invention is to provide a new and improved tool mechanism for deep rolling operations wherein the cage and retainer design for the tool includes the novel use of a special spring loaded cage structure.
Still another object of the present invention is to provide a newly designed tool mechanism for deep rolling operations which has an improved and unique cage and retainer design for holding the work rollers, and which also is designed such that the tool mechanism can be cleaned in conventional ultrasonic cleaning systems without disassembly.
Other objects features and advantages of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings (wherein like numerals indicate like elements).